In recent years, there has been a substantial technological effort directed toward the development of an improved engine as for use in automotive vehicles. The primary objectives of the effort have been improved efficiency and reduced pollution. Important secondary considerations for an engine have also been significant including: reduced size, economy of manufacture and relatively-low maintenance requirements.
Although some truly-significant recent advances have been accomplished in the field of fuel engines, a ponderous problem continues in relation to the utilization of existing production facilities and maintenance knowledge. That is, a prodigious quantity of tooling and machinery exists for the production of conventional internal-combustion engines as used in automotive vehicles. That fact tends to reduce the significance of improved engines that require totally-different tooling and production machinery. Consequently, the primary implemented efforts to reduce the flow of pollutants from internal-combustion engines have involved corrective appliances rather than improved combustion cycles. The result has been a questionable reduction in the emission of pollutants accompanied by a general reduction in engine efficiency and performance. Consequently, in view of the intensifying importance of conserving fuels, such prior efforts are questionable improvements in relation to the total situation.
In general, it is recognized that two forms of internal-combustion engines are relatively low in the production of polluting emissions. These engines are the Diesel and the stratified-charge Otto engine. Generally, Diesel engines tend to be noisy, relatively heavy, relatively expensive, somewhat unstable and although not highly productive of live hydrocarbons and nitrogen oxides, do produce substantial smoke. With regard to the stratified-charge Otto-cycle engine, the structure is relatively complex and, accordingly, expensive in that a plurality of carburetors must be synchronized. Additionally, the stratified-charge engine sacrifices efficiency due to a decrease in the compression ratio necessitated by the added space or chamber for inititating combustion.
Regardless of the individual considerations pertinent to stratified-charge and Diesel engines, the significant fact is that at present, neither engine may be readily embodied in a form similar to a conventional internal-combustion automotive engine for which vast production facilities and widespread maintenance knowledge currently exist. Engines of the present invention have similarities to Diesel and stratified-charge cycles and may be embodied forms for production and maintenance by a substantial fragment of existing facilities. That is, the present invention is directed to an improved internal-combustion engine which may be embodied in a form that is capable of manufacture utilizing substantially-conventional production facilities. The engine of the present invention burns fuel with an abundance of air, control being exercised by metering fueld independent of the air supplied to the engine. More specifically, the engine incorporates a fuel supply system for selectively injecting charges of fuel into the cylinder chambers at variable time intervals and in accordance with the demand for drive power. Each combustion involves a predetermined number of component or elemental fuel charges, which variation also affords a basis for control.
In the operation of an engine in accordance herewith, fuel is injected into cylinder chambers through heated passages which, in the illustrative embodiment, are incorporated in a spark-plug structure which also ignites the fuel charges. Fuel is supplied by the injectors in accordance with current power demand as necessary to: (1) maintain smooth operation of the engine, and (2) satisfy a demand for an output torque. In the disclosed embodiment, a manual control system develops digital control signals for actuating a fuel-control apparatus to inject component charges of fuel. Timely injection of the component fuel charges in relation to ignition accomplishes a relatively clean combustion that occurs substantially in accordance with demand and in an abundance of air.
It is recognized that systems have been previously proposed in which fuel is metered somewhat independent of the air intake to the engine. Such systems have been employed as for starting and controlling engines. Exemplary systems are disclosed in U.s. Pat. Nos. 2,030,086 (Woolson); 2,010,469 (Trienbnigg) and 3,719,176 (Shinoda et al). However, systems in accordance with the present invention wherein component fuel charges are selectively injected responsive to demand, and are effectively burned, are believed to represent a significant improvement.
Part of the subject matter of this disclosure is contained in Disclosure Document No. 019812 filed in the U.S. Patent Office on June 6, 1973. Also, part of the general principle of electronic digital control of internal combustion engines is included in Pat. Applications No. 298,824, filed Oct. 19, 1972, and No. 314,211, filed Dec. 11, 1972.